Crane truck



May 22, 1956 E. WlRZ 2,746,612

CRANE TRUCK Filed July 12, 1952 s Sheets-Sheet 2 INVENTOR ER N ST WIRZ 3? Sz MMMYL A GENTS May 22, 1956 E. WIRZ 2,746,612

CRANE TRUCK Filed July 12, 1952 3 Sheets-Sheet 3 "Hir- /N VE N TOR E'KN ST WIRZ Mam-s CRANE TRUCK Ernst Wirz, Uetikonam See, Switzerland Application July 12, 1952, Serial No. 298,546 x 7 Claims. (Cl. 212-59) This invention relates to crane trucksand its object is to provide a simple and easily to operate crane truck. Cranes mounted on trucks, so called crane trucks, usually have a swingable and rotatable arm .andta rope or cable winch by means of which the load may be liftedor lowered. The construction and the operation of such a crane truck is comparatively complicated.

The crane truck according to the present invention differs from known constructions in that it has a crane arm swingable in a vertical plane, which arm is provided with a driven, extensible part by means of which corresponding operations may be carried out.

This crane truck is of simple construction and easy to work with since it operates without a rope winch. Due to the driven extensible part, however, a sufliciently wide loading zone maybe obtained.

At the end of the extensible part a load hook may be fastened so that rope winches, hydraulic or mechanical tackle blocks can be completely dispensedwith.

The above mentionedextensible part may be arranged telescopically within the rigid portion of the crane arm and it may be hydraulically operated. Furthermore the movement of the crane arm within the vertical plane can also be effected by means of a hydraulic jack so that these two movements requiring relatively great power may be carried out by hydraulic means. The control elements required for the hydraulicjacks occupy little space and they may be easily placed-within the cabin of the crane truck.

The whole crane may be arranged above the cabin at the highest place of the truck, the cabin-serving at the same time as a supportingmember forthe crane.

The crane according to the present invention may serve for moving and loading heavy loads. The truck of the crane itself, provided it is of suitable length, may be used as a transport vehicle, the crane in this case being used for loading and unloading purposes.

If the truck of the crane is of short constructionit may be used as a crane tractor for any crane works and at the same time as a tractor for hauling trailers, which may be loaded and unloaded by means of the crane.

The truck carrying the crane may be in comparison to the working zone of extremely compact construction so that it may be used as a vehicle on the public streets.

To the accomplishment-of the above, and other objects, features and advantages, as may hereinafter appear the present invention is directed to-a crane truck as hereinafter described in detail and shown in the annexed drawv United States Patent Fig. 5 is an enlarged elevational view of a pulled-out supporting element,

Fig. 6 is a plan view of a pulled-out supporting element,

Fig. 7 is a diagrammatic representation of the control system forthe hydraulic jacks,

Fig. 8 is a section through a brake valve,

Fig. 9 shows a modification of the hinged suspension of the two lifting jacks, and

Fig. 10shows a section along the line X-X of Fig. 9.

Referring now to Fig. 1 the numeral 1 designates a relatively rigid crane arm having an extensible part 2 telescoping therein, with the front end 3 of'the extensible part being tapered. A guiding channel is formed into this front end 3 to receive an extension part 4 to which the load hook 5 is fastened. Theextension part 4 is secured by means of bolts 6. Any special device for picking up the load may be provided at this place instead of the hook 5. Within the front part of the crane arm 1 rollers-7 are inserted and in the rear part of the extensible part 2 rollers 8 are inserted. The rollers 7 and 8 respectively engage the part 2 and'the arm 1 and serve to reduce the friction of the extensible part 2'when the latter is moved within the crane arm 1.

A double-acting, hydraulic jack 9 is provided for elfecting the pushing out and the pulling back of, the extensible part 2. The hydraulic jack 9 is held at one end. in a bearing 10 of the crane arm 1 and at the other end is journalled in a bearing 11 of the extensible part. By retracting and extending the extensible part 2, heavy loads may be pulled near or pushed away in any crane-position. Thusthe extensible part 2 not only serves as an extension of the rigid crane arm 1 but also for carrying-out work movements. The power-ratio for these movements are especially favourable on account of the central arrangement of the hydraulic jack 9.

The crane arm 1 is journalled between two supports 12 in two bearings 13. It is a feature of the present invention, that these bearings are placed at the topmost position of the truck and that they straddle the rigi crane arm 1.

A further feature of this invention consists in the fact that the crane arm 1 projects beyond its bearing support so than an extensible part 2 of great length can be placed in the interior of said arm 1.

The arrangement according to this invention contributes particularly to the possibility of providing-a small movable tractor with a far reaching crane arm. In order to enhance the lateral stability of the crane arm 1 sheet metal guides 12' (shown in broken lines on Fig. 1) are provided on the supports 12. The rigid crane arm 1 slides between these sheet metal guides 12' when it is moved up and down. Two hydraulic jacks 14, which bear, as at 15, against the crane arm 1 (Fig. 2), are journalled in the downward projecting parts 12" of the two supports 12 (Fig. 1). These two jacks 14 are provided for efiecting the vertical movements of crane arrnl, that is, the movements about the horizontal bearings 13. Since these jacks 14 extend downwards at the side of the cabin, they may be quite long, thereby to providea correspondingly extended lift. Thereby a great vertical lift of the crane hook is attained without enlarging the structural height of the truck as illustrated in Fig. 4, which shows the crane arm I raised or elevated by the jack 14 and the extension 2 in drawn-out position.

The crane arm 1 together with the supports 12 and the jacks 14 are rotatably arranged upon the cabin roof of the truck. It is essential that according to the present invention a ring thrust-bearing 16, 17, 18 forming a revolving platform be used as a bearing support for'the crane. Such a ring thrust-bearing has the advantage of providing a low or fiat construction. cabin roof 19 is fastened to the ring 18.

The arch-shaped cabin roof 19 has the advantage that sufficiently ample room is provided for the operator. Through this arrangement the height of the truck can be reduced. The stationary lower part 16 of the ring bearing is at the same time a structural part of a round cabin of great strength or carrying capacity. The race 18 of the thrust bearing is provided with internal teeth 18'. A reversible gearing 20, driven by the truck motor 31 and operatable by the lever 21 effects the turning motion of the crane. The power is transmitted from the gearing 20 by the upright shaft 22 and the gearing 23 meshing with the internal teeth 18' of the race 18 (Fig. 3). A special advantage of this arrangement consists in that the shaft 22 may be placed close to the outer wall of the cabin. The numeral 24 designates the automotive gearing or transmission by means of which the reversible gearing 20 is driven by the shaft 25. 26 is one of the upright support columns of the supporting cabin of the operator. The cabin support columns 26 are joined to each other by the lower part 16 of the ring thrust hearing. The cabin 27 is of circular construction in order to provide clearance for the crane parts 12" and 14 projecting downwards along the outer wall of said cabin, during the rotary movement of the crane. Due to said circular construction of the cabin, moreover, the operator is provided with a good view and can observe from all sides the movements of the crane which facilitates the control of the latter. A loading bridge 28 serves as further stiffening support of the cabin. The operator seat 29 with the controls is located in the middle of the cabin, that is, over the longitudinal axis of the vehicle. The seat 29 of the operator is mounted upon a swivel socket 30 rotatable to a certain extent. The low lying construction is an essential feature of the whole crane truck. For this reason and in order to provide a favourable weight-distribution, the motor 31 is placed not over the front axle of the vehicle but in front of same and the transmission 24 is arranged behind the front axle. The floor 32 of the cabin therefore can be placed comparatively low even below the upper edge of the chassis frame 33. The above described construction also allows the use of strong, straight, longitudinal chassis supports 33.

For handling heavy loads additional supporting devices for the truck are required. For this purpose rectangular transverse tubes 34 are provided underneath the chassis frame 33 and secured to the latter. These transverse tubes 34 form at the same time connecting elements for the chassis 33, while the centrally located transverse tubes m()l OVC1 serve as abutments for lateral supports of the ca in.

The tubes 34, as shown in Figs. and 6, are adapted to receive extensible supports 35, at the outer ends of which hydraulic support jacks 36 are mounted. In order to be able to draw out said supports 35 as far as possible, they are of the same maximum length as the transverse tubes 34 which for their part are approximately as long as the width of the truck. In order to avoid the necessity of rearranging the supports 35 when the crane is moved from one side to the other of the truck, six transverse tubes 34 are provided so that four to six mounted support devices can be carried along.

It is to be understood that if required, additional swingable supporting devices, such as the device 37 shown in Fig. I, can be attached to the truck. The support 35 is adapted to be pulled out by hand, while the hydraulic supporting jacks 36 are operated by a suitable pump driven by means of the motor.

The hydraulic jacks 36 are connected by means of conduits 38 with a common pump 39 and by means of conduits 40 with an oil tank 41 (Fig. 6). By means of a three-way cock 42 oil can be led to the supporting jacks or back to the tank. It is of importance that the conduits 38, 40 be continuously connected with the jacks 36 and An arch-shaped need not be disconnected to permit lateral movement of the supports 35. For this reason portions of the conduits 38, 40 are formed of rubber hose with a loop 43 therein. The hydraulic operation of the jacks 36 is carried out in the following way:

The operator puts the oil pump 39 of the supporting devices in operation. The oil pump provides a pressure greater than that determined by a pressure release valve 44. The operator leaves his seat in the cabin, adjusts the supports to the required drawn-out position and by means of the three-way cock 42 charges each of the hydraulic supporting jacks according to his judgment. After such positioning of the supporting arrangement, the operator can shut off the support pump 39 and may operate the crane in the desired zone. Before starting to drive away, the various supporting elements are drawn in again by adjusting the three-way cock 42 for return-flow. The oil contained in the jack 36 is caused to flow back into the tank by the retraction of the jack by the action of the spring 45 in the latter, whereupon the extensible support 35 together with the supporting jack 36 can be pushed back into the tube 34.

The hydraulic control (see Fig. 7) represents an essential element of the present invention enabling simple operation of the crane.

For each individual kind of motion, as a matter of principle, an individual lever is provided, thus a lever 46 controls the lifting and lowering movement, a lever 47 controls the pulling-out and pulling-back movement and a lever 21 (Fig. 1) controls the mechanical slewing movement in two directions.

For this reason it is possible to carry out all motions simultaneously or, if desired, individually.

For effecting the rotary or slewing movement the reversible gearing 20 is controlled by manipulation of the lever 21 (Fig. 1).

The hydraulic control system for the crane movements is illustrated in Fig. 7, wherein 48 designates the oil tank, 49 a pump driven by the motor of the truck, which pump actuates the double-acting jack 9 of the extensible crane arm; 50 is a pump for actuating the two jacks 14 which effect the lifting movement, 51 is a reversing valve for controlling the jack 9 and which is actuated by the lever 47, which lever may be adjusted to any of three positions: Idling, Push-out, and Pull-in; 52 is a reversing valve for controlling the fiow to the hydraulic lifting jacks 14 and which is actuated by the lever 46, which may be set in any of three positions: Stop, Lift and Lower; 53 is a safety valve which is adjusted to the required pressure in thejack 9; 54 is a safety valve which is adjusted for the required pressure in the jacks 14.

It is essential that that portion of the hydraulic system, consisting of pump 49, reversing valve 51 and safety valve 53, associated with the jack 9 is completely independent of the portions of the hydraulic system associated with the jacks 14. Only the oil tank 48 can be common to both portions of the system.

The construction of the reversing valves, the safety valves, the pumps and the connecting conduits corresponds generally to the conventional designs.

The numeral 55 represents a rotary coupling for the various oil conduits, located upon the rotatable arch 19 of the cabin, forming the movable connection between the conduits and the stationary truck.

The member 56 within the rotary coupling 55 is stationary and provided with conduit connections for the conduits coming from the reversing valves. Furthermore the member 56 has borings for leading the oil to the re spective outlets in the rotary coupling 55.

The numeral 57 designates brake valves on the lifting jacks'14 which in case of conduit failure prevent the load from falling. Fig. 8 shows a section of such a valve. By action of the load upon the jacks 14 the oil flows through the conduit 58 into the valve and leaves the latter through the conduit 59 which leads back to the oil tank.

Under normal operative conditions oil flows through the opened valve 60. It for any reason the oil velocity increases beyond a permissible amount, the valve 60 is closed by the increased velocity of the stream and only a passage of small cross-section remains open, whereby the lowering speed of the jacks 14 and consequently of the load is reduced.

In the modification illustrated in Figs. 9 and 10, the hydraulic lifting jacks 14 are journalled in forked parts 62 by means of pivots 61, the parts 62 being riveted to the supports 12. The lifting jacks 14 thus lie within the plane of the supports 12 so that those supports can be located relatively close to each other (as can be seen by comparing Fig. 2 and Fig. and in this case only the lifting jacks 14 project down at the side of the cabin so that the obstruction to the view is thereby decreased.

What I claim is:

l. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on a truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, and hook means fixed directly to the free end of said second member.

2. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting said crane support on a truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, said hydraulic jack being disposed in the interior of said first and second telescopically mounted members of the crane arm, and hook means fixed directly to the free end of said second member.

3. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on the truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, an operators cabin on said truck, said annular thrust bearing being arranged on the upper end of the cabin, said thrust bearing including a lower part constituting an upper ring-shaped stifiening member for the operators cabin, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, and hook means fixed directly to the free end of said second member.

4. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on the truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, an operators cabin on the truck, said annular thrust bearing being arranged on the upper end of the cabin, the lower part of the thrust bearing constituting an upper ring-shaped stiffening member for the operators cabin, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, said hydraulic jack being disposed in the interior of said first and second telescopically mounted members of the crane arm, and hook means fixed directly to the free end of said second member.

5. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on a truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, said hydraulic jack being arranged in the interior of said first and second telescopically mounted members of the crane arm, said first hollow member of the crane arm extending rearwardly beyond the pivoting axis of the crane arm, and. hook means fixed directly to the free end of said second member.

6. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on a truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same. time reducing the height of the truck, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said hydraulic means comprising lifting jacks journalled in downwardly extending projections of the rotatable crane support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, a hydraulic jack for extending and retracting said second member, said hydraulic jack being arranged in the interior of said first and second telescopically mounted members of the crane arm, and hook means fixed directly to the free end of the second member.

7. A crane truck comprising, a rotatable full-circle crane support, an annular thrust bearing mounting the crane support on a truck, an arch within said annular thrust-bearing providing a free space for the crane operator and at the same time reducing the height of the truck, a crane arm pivotally connected to said support for pivoting movement in a vertical plane, hydraulic means for pivoting said crane arm with respect to said support, said crane arm comprising a first hollow member, a second member telescopically mounted in said first member, said hydraulic means comprising lifting jacks journalled at their upper portion directly to said first hollow member, a hydraulic jack for extending and retracting said second member, said hydraulic jack being arranged in the interior of said first and second telescopically mounted members of the crane arm, and hook means fixed directly to the free end of said second member,

References Cited in the file of this patent UNITED STATES PATENTS 2,196,649 Waite Apr. 9, 1940 2,446,586 Harbaugh' Aug. 10, 1948 2,462,926 Wilson et a1 Mar. 1, 1949 2,475,963 Howell July 12, 1949 2,558,686 Hubbard June 26, 1951 2,684,159 Oldenkamp July 20, 1954 FOREIGN PATENTS 548,193 France Oct. 14, 1922 

